Several molecular genetic alterations have been characterized in gliomas in the past years. Molecular profiles have been associated with specific histologic and prognostic tumor subgroups, contributing to improve the classification of gliomas. At least two alternative molecular pathways have been suggested in the astrocytoma progression involving TP53 inactivation (secondary glioblastomas) and EGFR amplification (de novo glioblastomas) respectively. Oligodendroglial tumors have demonstrated recurrent combined loss of chromosome 1p/19q, which represent a favorable prognosis marker and probably a predictor of a good chemosensitivity of the tumor. This review discusses recent molecular advances and clinical implications with special focus on oligodendroglial tumors.